Automatic feeding, power-operated envelope opener

ABSTRACT

An automatic feeding, power-operated envelope opener which is operative in such a manner that, when a switch actuating lever is operated by an envelope travelling on an envelope mounting table, an on-off switch of the opener is actuated to set an electric motor in motion and two rotary cutter elements whose shafts are slightly inclined relative to each other are driven by the drive of said motor through a transmission gearing, with the peripheral edge portions thereof in contact with each other at an acute angle, whereby the envelope is cut at one edge by the coaction of said rotary cutter elements.

United States Patent [1 1 Amakawa et a1.

[ AUTOMATIC FEEDING,

POWER-OPERATED ENVELOPE OPENER {75] Inventors: Saichi Amakawa; Osamu Miyamoto,

both of Moriguchi; Akito Kawamoto, Neyagawa; Hiroshi Kawai, Moriguchi, all of J apan [73] Assignee: Matsushita Electric Industrial Co.,

Ltd., Osaka, Japan 22 Filed: Nov. 16, 1970 [21] Appl. No.: 89,554

[30] Foreign Application Priority Data June 19, 1973 3,143,024 8/1964 Markowski 83/501 X 3,185,010 5/1965 Printz 83/501 X 2,027,045 1/1936 Keiser 83/912 X 3,455,094 7/1969 Gorham 83/501 X 1,158,583 11/1915 Taylor 1 83/493 X 1,210,454 1/1917 Gagne 1 83/493 1,274,623 8/1918 Spiegelm. 83/333 1,642,998 9/1927 Mason 83/496 X 3,204,503 9/1965 Simjian 83/210 X Primary ExaminerAndrew R Juhasz Attorney-Stevens, Davis, Miller & Mosher [5 7] ABSTRACT An automatic feeding, power-operated envelope opener which is operative in such a manner that, when a switch actuating lever is operated by an envelope travelling on an envelope mounting table, an on-off switch of the opener is actuated to set an electric motor in motion and two rotary cutter elements whose shafts are slightly inclined relative to each other are driven by the drive of said motor through a transmission gearing, with the peripheral edge portions thereof in contact with each other at an acute angle, whereby the envelope is cut at one edge by the coaction of said rotary cutter elements.

14 Claims, 28 Drawing Figures FIG.

FIG. I8

FIG. l9 H4 FIG. 20 be k Km ld9llllli0l FIG. 2|

I22 121 I20 n9 PMENIEU saw a or 9 FIG. 24

AUTOMATIC FEEDING, POWER-OPERATED ENVELOPE OPENER The present invention relates to an envelope opener which is capable of cutting one edge of an envelope without cutting the content of the envelope, and more particularly to such an envelope opener which includes two cooperating cutter elements arranged one on top of another in such a manner that one of them is just slightly inclined relative to the direction of travel of an envelope so that they are held in contact with each other, and driven from a drive source, whereby the envelope being fed on an envelope mounting table by a feed roller is cut at one edge in a satisfactory manner.

The first object of the present invention is to provide an automatic feeding, power-operated envelope opener wherein one of two cutters is arranged parallel to and the other one is arranged at a very small angle to the direction of travel of an envelope so that both cutters are held in contact with each other and penetrate into the envelope in the manner of a wedge, whereby the envelope is cut at one edge positively.

The second object of the invention is to provide an automatic feeding, power-operated envelope opener wherein a switch actuating lever is operated by an envelope travelling on an envelope mounting table, to actuate a drive source and a cutting mechanism is operated only when the envelope is fed in the opener, whereby wasteful power consumption is avoided and the safety character of the opener is enhanced.

The third object of the invention is to provide an automatic feeding, power-operated envelope opener wherein a guide portion having a U-shaped crosssection is formed at an edge of an envelope mounting table integrally therewith and said guide portion is bulged at the portion opposite to two rotating upper and lower cutter elements in a direction to move away from said cutter elements, whereby discharge of the cut chip of the envelope is facilitated and displacement of the envelope during travel of the same is prevented by the upright portion of said guide portion and further curling of the envelope edge upwardly is prevented by a pentroof formed at the upper edge of said upright portion.

The fourth object of the invention is to provide an automatic feeding, power-operated envelope opener wherein a small elongated table is mounted on one edge of an envelope mounting table adjacent cutter means in such a manner that it is movable in a direction perpendicular to the longitudinal direction thereof, whereby the width of the cut chip of an envelope can be varied.

The fifth object of the invention is to provide an automatic feeding, power-operated envelope opener wherein two cutters are arranged in contact with each other and the peripheral speeds of said two cutters are varied from each other, whereby said cutters are sharpened by each other during rotation and the cutting efficiency of the cutters is maintained.

According to the present invention there is provided an automatic feeding, power-operated envelope opener which comprises cutter means including two cutters arranged vertically in such a manner that one of them is parallel to and the other one is inclined at a very small angle to the direction of travel of an envelope to be opened and driven with the peripheral edge portions thereof in engagement with each other to penetrate into the envelope in the manner of wedge, an electric motor constituting a drive source, a table for mounting the envelope thereon, an on-off switch for controlling the current supply to the opener, a switch actuating lever for actuating said switch to supply current to said electric motor upon being operated by the envelope travelling on said table, a feed roller for feeding the envelope to said cutter means and a transmission gearing for transmitting the drive of said electric motor to said cutter means and said envelope feeding roller.

Other objects, features and advantages of the present invention will become apparent from the following description on the embodiments thereof when taken in conjunction with the accompanying drawings, in which:

FIGS. 1 and 2 show a portion of the automatic feeding, power-operated envelope opener according to the present invention, which is common for the two embodiments of the invention described and illustrated herein, and of which FIG. 1 is a top plan view and FIG. 2 is a side elevational view;

FIGS. 3 to 6 inclusive show the first embodiment of the automatic feeding, power-operated envelope opener according to the present invention, of which FIG. 3 is a top plan view showing the mechanism of the opener; FIG. 4 is a front elevational view of the mechanism; FIG. 5 is a side elevational view of cutter means and a power transmitting gearing; and FIG. 6 is a perspective view showing, in explosion, the entire mechanism less a motor;

FIGS. 7 to 10 inclusive show a portion of the automatic feeding, power operated envelope opener, which is common for said embodiment and the embodiment to be described later, and of which FIG. 7 is a side elevational view of the motor mounted on a base plate; FIG. 8 is a top plan view of an upper cutter and a lower cutter in engagement with each other; FIG. 9 is a top plan view of a bearing which supports the lower cutter; and FIG. 10 is a cross-sectional view of a structure to secure the bearing shown in FIG. 9;

FIGS. 11 to 21 inclusive show the second embodi ment of the automatic feeding, power operated envelope opener according to the present invention, of which FIG. 11 is a top plan view of the mechanism of the opener; FIG. 12 is a front elevational view of the mechanism shown in FIG. 11 FIG. 13 is a side elevational view showing the relative position of the cutter means and the upright portion of a movable small table; FIG. 14 is a top plan view of a portion of the small table; FIG. 15 is a front elevational view of the small table shown in FIG. 14; FIG. 16 is a view showing the relative position of the small table shown in FIG. 15 and the cutter means; FIG. 17 is a top plan. view of the entire small table; FIG. 18 is a front elevational view of the table shown in FIG. 17; FIG. 19 is an end view of the small table; FIG. 20 is a fragmentary top plan view of an envelope mounting table having a pair of engaging slots formed therein for engagement with said small table; and FIG. 21 is a view showing parts to be provided on each pin on said small table; and

FIGS. 22 to 278 inclusive show a portion of the auto matic feeding, power-operated envelope opener, which is common for both the embodiments described herein, and of which FIG. 22 is a bottom view showing the half of a cover; FIG. 23 is a cross-sectional view of the cover; FIG. 24 is a side elevational view of a case; FIG. 25 is a fragmentary cross-sectional view of the case with legs mounted thereon; FIG. 26 is a top plan view of a leg mounting seat provided on the case; FIG. 27A is a top plan view of the leg and FIG. 27B is a crosssectional view of the leg.

Referring to FIG. 1, reference numeral designates a cover made of polyamide (nylon) and 11 designates a table for placing an envelope to be cut thereon, which is made from aluminum sheet and has a corrosionresistant film formed on the upper surface thereof after sand brushing. Reference numeral 12 designates a boxshaped case produced by stamping a steel sheet. The cover 10, as shown in FIGS. 22 and 23, has the front portion thereof cut away to form an opening 13 and has projections 15 integrally formed on the inside surfaces of the side walls thereof in opposed relation, said projections each having a nut embedded therein for engagement with a tightening bolt 14. Further, a rectangular lip 19 is formed on each side wall of the cover 10 at the inner edge of the opening 13, extending downwardly for interlocking engagement with a rectangular notch 16 formed in each side wall of the case 12. Two downwardly extending projections 18 are formed at the root of each of the projections 15, with a gap formed between them and a step 17 formed in the undersurface of the wall of the cover 10.

These projections 18 engage the inside surface of the case 12 when the cover 10 is fitted to the case 12 with the step 17 in engagement with the top surface 20 of the wall of said case 12, thereby to prevent a transverse displacement of said cover relative to said case. A longitudinal displacement of the cover 10 relative to the case 12 is prevented by the interlocking engagement between te rectangular lips 19 and the notches 16 formed in the case. Referring to FIG. 24, reference numeral 21 designates through-holes for the insertion of the tightening bolts 14, and 22 designates three elongate air inlet openings formed in the rear end wall of the case. A large number of exhaust apertures are formed in the bottom wall of the case, though not apparent in the drawings.

The case 12 has a mechanism shown in FIGS. 3 and 4 fixedly mounted therein by means of bolts. The mechanism includes a plated L-shaped steel base plate 23 and the aforesaid table 11. A motor 25 as a driving source is fixedly mounted on the horizontal portion 24 of the base plate and a small diameter drive gear 27 having 14 teeth is integrally fixedly mounted on one end of a motor shaft 26, said drive gear being made of a polyacetal resin highly resistive to wear and having a small coefficient of friction. On the other end of the motor shaft 26 is mounted a cooling fan 28 made of aluminum. The cooling fan 28 simultaneously serves as a flywheel for smoothening the rotation of the motor 25, while cooling said motor by blowing air, sucked through the openings 22 in the case 12, against the stator portion of the motor. The motor 25 is secured to the horizontal portion 24 of the base plate 23 by four bolts 29 as shown in FIG. 7. Reference numeral 30 designates bearings for the motor shaft. The table 11 mentioned above is connected to the outside surface of the upright portion 31 of the L-shaped steel base plate 23. On the upright portion 31 of the base plate 23 are provided gear means 32 for transmitting the drive of the motor to an envelope cutter and a feed roller for feeding an envelope E to be cut to the cutter portion, and a switch lever mechanism for operating a microswitch 33 upon engagement with the envelope being fed.

The gear means 32 comprises three gears consisting of a gear for a lower cutter which meshes directly with the drive gear 27 fixed on the motor shaft 26, a gear 36 for the feed roller which also meshes directly with the drive gear 27, and a gear 38 for an upper cutter which meshes with a small gear 37 coaxial with said gear 34. These three gears are made of the same material as the material of the drive gear 27 mentioned above, and are formed in the same configuration in consideration of interchangeability and economy, i.e. in the configuration of a large gear having 42 teeth and a small gear having 14 teeth integrally coaxially connected with each other. The three gears 34, 36 and 38 are fixedly mounted on one ends of rotary shafts 39, 35 and 40 in force-fit engagement therewith respectively, and these rotary shafts 39, 35 and 40 are joumaled through gearings provided on the upright portion 31 of the base plate 23.

Each of the bearings includes a cylindrical housing 41 formed by pressing on the upright portion 31 and a sleeve-shaped bearing metal 42 forced into said cylindrical housing 41 and made of a sintered iron-base alloy.

Of these bearings, the bearing to support the shaft 39 only is slightly, i.e. about 30 minutes, inclined with respect to a line normal to the upright portion 31, as shown in FIG. 10, by hitting the housing of said bearing from the outside of the upright portion with a slightly inclined punch after formation of the same, and hence the axis of the bearing metal 42 telescoped into said housing 41 with force is also inclined about 30 minutes with respect to a line normal to the upright portion 31 as shown in FIG. 9.

Therefore, when a disc cutter 43 of 23 mm in diameter and a disc cutter 44 of 12 mm in diameter, each having a tapered edge, are mounted on the upper cutter shaft 40 and the lower cutter shaft 39 and fixed thereon through a locking washer 45 and a plain washer 46, by screw-threading a nut 47 onto a threaded portion 48 at an ends of said shafts respectively, both cutters 43, 44 contact each other as shown in FIGS. 4 and 5.

In this case, since the bearing metal 42 to support the shaft 39 of the lower cutter 44 is about 30 minutes inclined relative to the shaft 40 of the upper cutter 43 as stated above, both cutters 43, 44 are not parallel to each other but in plane contact at very narrow portions thereof.

As stated above, the cutters 43, 44 are both formed into a disc-shape, but in the surface of larger area of each cutter, i.e. in the surface of the larger cutter 43 facing the upright portion 31 of the base plate 23 and in the surface of the smaller cutter 44 facing the table 11, is formed a shallow circular recess as indicated by the broken line in FIG. 8 and these cutter are in contact with each other at very small areas of the peripheral edge portions thereof. An L-shaped plate spring 52 is fixed at one end on the horizontal portion 24 of the base plate 23 by a bolt 50 with a locking washer 51 interposed therebetween, and the other end thereof is in pressure engagement with that end of the lower cutter shaft 39 on which the gear 34 is mounted, as shown in FIGS. 5 and 6. Therefore, the small diameter lower cutter mounted on the other end of the shaft 39 is constantly urged toward the table 11 and held in pressure contact with the peripheral edge of the large diameter upper cutter 43. Thus, a satisfactory contact between thecutters 43 and 44, as described above, can bemaintained over an extended period.

The upper cutter shaft 40 is provided with an annular groove 54 and an E-shaped washer 53 is fitted in said annular groove to ensure that the upper cutter 43 will not be axially displaced under the biasing force of the lower cutter 44. The feed roller shaft 35 is also provided with an annular groove 56 for receiving an E- shaped washer 55 to prevent an axial displacement of said shaft.

One end of the feed roller shaft 35 is slightly smaller in diameter than the other portion and a feed roller 57 of synthetic rubber is mounted thereon in force-fit en gagement therewith.

A pin 58 is fixed to the front surface of the left side portion of the upright portion 31 at an upper portion thereof and a roller supporting arm 59 is mounted on said pin 58 for vertical pivotal movement thereabout. In this case, the roller supporting arm 59 is mounted on the pivot pin 58 in such a manner that said pivot pin 58 extends through holes formed in the opposite walls of a U-shaped end 60 of said arm, so as to prevent rattling of said arm during pivotal movement thereof. The other end of the roller supporting arm is provided with a pin 62 for mounting a follower feed roller 61.

The roller 61 is mounted on the pin 62, with the latter extending through a through-hole 63 formed in the former, and an E-shaped washer 64 is fitted on the projecting end of the pin 62 to ensure that said roller will not come off the pin. The arm 59 is not completely flat but is slightly bent toward the upright portion of the base plate, so that the follower feed roller 61 and the driving feed roller 57 are in contact with each other one on top of the other, with the axes thereof crossing each other. Namely, by bending the free end of arm 59 toward the upright portion 31 of the base plate, the axis of the follower feed roller 61 is 3 degrees inclined relative to the direction of travel of the envelope, so that the envelope E to be cut is always held in contact at one edge with an upright portion of the table to be described later.

The follower feed roller 61 is constantly urged downwardly by a coiled spring 65 which is loosely mounted on the pivot pin 58, with one end thereof hooked on the upper edge of the upright portion 31 and the other end on the central portion of the arm 59. Therefore, when the roller 57 is rotated, the roller 61 is driven in contact with said roller 57 in a direction opposite to the rotating direction of the latter. Reference numeral 67 designates an E-shaped washer fixed on the free end of the pin 58 to keep the follower feed roller 61 on said pin.

A switch actuating lever 66 is provided on the right side of the follower feed roller 61 to actuate the aforesaid microswitch 33, upon being operated by the envelope fed in. This lever 66 has ,one end 68 thereof formed into aU-shape and is loosely mounted on a pivot pin 69 fixed to the upright portion 31, with said pivot pin extending through holesformed in the opposed walls of said U-shaped end. An arm 70 of the lever 66 is mildly flexed in an L-shape and extends downwardly of the table through a slot 71 formed in said table. Similar to the arm 59 of the feed roller, the switch actuating lever 66 is biased downwardly by a coiled spring 72 which is loosely mounted on the pivot pin 69, with one end thereof hooked on the upper edge of the upright portion 31 and the other end on a portion of said lever. A tongue 73 is integrally formed with the U-shaped end 68 of the upright lever 66 for depressing a contact 75 of the microswitch 33. Reference numeral 74 designates an E-shaped washer mounted on the free end of the pivot pin 69 to keep the U-shaped end of the lever 66 on said pivot pin.

The microswitch 33 is fixed to the upper portion of the upright portion 31 by means of a bolt 76 and held in an off-position when the envelope opener is inoperative, with the contact thereof being depressed by the tongue 73 of the lever 66. Reference numeral 77 designates a protective plate consisting of a fiber plate, by which a cut chip of the envelope is prevented from entering the gear portion 32.

Now, the table 11 on which the envelope to be cut is fed into the cutting portion, will. be described: The table 11 is made from an aluminum sheet as stated previously. That edge of the table 1 1 which is fixed to the upright portion 31 of the base plate 23 is shaped into a U-shape to form an upright portion 78 which serves as a guide for the envelope, and a pentroof 79 which prevents the inner edge of the envelope from curling upwardly.

In the present invention, particularly the portion 80 of the U-shaped edge of the table, extending from the mid portion between the feed rollers and the cutter to the rightward end of the table, is slightly bulged outwardly or toward the upright portion of the base plate, so as to make the distance between the portion of engagement between the cutters 44, 43, and the upright portion 78 of the table, slightly larger than at the other portion. This is for the purpose of facilitating the discharge of the cut chip of the envelope to the right side of the opener.

In addition to the slot 71 formed longitudinally in the table 11 for projecting the switch actuating lever66 downwardly of the table, a semicircular opening 81 is formed in the table, through which the lower half portion of the lower cutter 44 projects downwardly of the table, and further an opening 82 is formed in the table in communication with said slot 71, to receive the driving feed roller 57. A notch 83 is formed at a portion of the pentroof 79 for receiving the upper cutter shaft 40. Three bolts 84 are provided on the table 1 1, projecting from the backside of the upright portion 78 thereof, and two of them which are located leftwards of the feed rollers, extend through the upright portion of the base plate to tighten the same from both sides by nuts 85a, 85b through a locking washer 86 and the rightwardmost one of them extends through both the protective plate 77 and the upright portion of the base plate to tighten the same from the backside thereof by a nut 88 through a locking washer 87.

In FlGS. 1 and 3, reference numeral 89 designates a manually operative tumbler switch for controlling the current supply to the opener, which is fixed to a side wall of the case 12 by bolts and which flows a current, supplied through a power cord 90, to the microswitch 33 and the motor 25 therethrough when it is in an on position. The power cord 90 extends into the case 12 through the rear end wall of said case, with a shielding member 91 provided between it and the case, and is connected to one of the lead wires of the motor 25 and one of the lead wires of the tumbler switch 89. The other lead wire of the motor 25 and the other lead wire of the tumbler switch 89, are connected to two terminals of the microswitch 33.

As shown in FIG. 3, the horizontal portion 23 of the base plate 23 is formed with four internally threaded holes, i.e. holes 92, 93, 94 and a hole formed below the bearing metal 42 for the cutter. On the other hand, the bottom wall of the case 12 is formed with four inwardly projecting mounting seats 95 of the type shown in FIG. 26 at locations corresponding to the aforesaid internally threaded holes of the base plate 23 respectively, and a substantially oval leg mounting hole 96 is formed through the center of the raised portion of each mounting seat 95. A synthetic rubber leg 97 of the structure shown in FIG; 27 is fitted in the hole 96. The leg 97, as shown in FIGS. 27A and 27B, comprises a main body 100 having the outer peripheral surface tapered and having a bolt receiving bore 99 axially formed therein from the inclined bottom surface 98 thereof, an engaging portion 101 having the same diameter and same cross-sectional shape as those of the oval leg mounting hole 96 and a circular flange 102 formed on top of said engaging portion 101, all of which are integrally molded of a synthetic rubber. A throughhole 103 is bored centrally through the engaging portion 101 and the flange 102 in communication with the bolt receiving bore 99.

Of the legs 97 to be mounted on these four mounting seats 96, the two legs at the forward portion of the case or closer to the table 11 have the main bodies 100a thereof longer in length than the main bodies 100b of the other two legs at the rear portion of the case, so that the opener, when set on a desk or the like, is inclined as a whole upwardly from the motor side to the table side thereof. Such inclination of the opener enables the envelope E, placed on the table, to be held in contact with the upright portion 78 of the table 11 at one edge thereof so that said edge of the envelope may be cut easily.

Each leg 97 is fixed to the case 12 together with the base plate 23 by a bolt 104 which is inserted into the axial bore 99 of said let to extend through the throughhole 103 of the same and threaded into an internally threaded hole formed in said base plate. The flange 102 of each leg serves as a cushion for the horizontal portion 24 of the base plate 23, so that a vibration or noise caused by the rotating motor 25 and transmitted to the base plate 23 are clamped by being adsorbed by said flange and consequently only a slight amount, if any, of such vibration or noise is transmitted to the case 12. Therefore, the cutting operation is not interfered by the vibration of the motor and the envelope can be cut smoothly satisfactorily.

The envelope opener of the invention constructed as described above operates in the following manner: As stated above, the opener itself is inclined as shown in FIG. 2. Therefore, when an envelope E to be opened is placed on the inclined table 11 as shown in FIGS. 1 and 3, the edge to be cut of the envelope E abuts against the upright portion 78 of the table 11. In this case, the tumbler switch 89 of the opener is of course placed in an on-position to connect the motor 25 and the microswitch 33 to a power source. The envelope E on the table 11 is moved by finger tips from the upper side to the lower side of FIG. 1 or from the left side to the right side of FIG. 3 and, when it is located close to the feed roller 61, the switch actuating lever 66 is pivot ally moved upwardly by the leading edge of the envelope. The pivotal movement of the switch actuating lever 66 results in a downward movement of the tongue 73 which has held the microswitch 33 in an off-position by engagement with the contact 75, and thus releases said contact 75 to place said microswitch in an onposition. Consequently, the motor 25 is set in motion to rotate the driving feed roller 57 and the upper and lower cutters 43, 44.

As the envelope E is further advanced from the position where it engages the lever 66, it is caught into the nip of the driving feed roller 57 and the counter rotating follower feed roller 61 driven by said driving feed roller 57, and moved from the left side to the right side of FIG. 3 by said feed rollers. In this case, since the axis of the follower feed roller 61 is 3 degrees inclined relative to the axis of the driving feed roller 57 as described previously, the edge to be cut of the envelope is held in contact with the upright portion 78 of the table 11, and during movement of the envelope in the manner described, the edge of the envelope is cut by the engaging portions of the upper and lower cutters 43, 44 which contact each other at an acute angle.

The arm of the switch actuating lever 66 is still located within the slot 71 of the table 11 at the point where said lever has actuated the switch 33, but is pushed above said slot 71 by the envelope at the point where said envelope has passed the nip of the feed rollers 57, 61.

Therefore, the switch 33 is held in the on-position until after the envelope E has passed through the rollers and the lever 66 has dropped again with the tongue 73 pushing the contact 75 of said switch 33, and the cutters 43, 44 are kept rotating in contact with each other throughout this period. The envelope is cut from the leading edge to a point adjacent the trailing edge thereof, by the rotation of the motor 25 driven by the power supplied thereto, and the remaining portion of the envelope is cut by the rotation of the motor under inertia after the switch is turned off.

The cut chip of the envelope can be easily discharged from the right end of the table 11 as the distance be tween the place of engagement between the cutters 43, 44, and the upright portion 78 of the U-shaped guide 80 is made larger at the portion of said guide from the mid portion between the two feed rollers 57, 61 and the cutters 43, 44 to the right end of the table than at the other portion as described previously. Curling of the cut chip of the envelope can be prevented by the pentroof portion of the U-shaped guide 80. The upper and lower cutters 43, 44 contact each other at an actue angle at the very small areas on the peripheral edge portions thereof as shown in FIG. 8, but the peripheral speeds of both cutters 43, 44 vary by reason of the outer diameters of said cutters and the rates of rotation of the rotary shafts 40, 39 of the same. Namely, since the gear ratio is 3 l, the upper cutter 43 of large diameter makes one revolution during three revolutions of the lower cutter 44 of small diameter and, since the outer diameter ratio of the upper and lower cutters is 23 12, the peripheral speed of the lower cutter 44 is 753.60 mm per second and that of the upper cutter 43 is 481.47 mm per second when the motor 25 is driven at 3,600 rpm. Because of such difference in peripheral speed between the two cutters, a relative movement occurs between the peripheral edge portion of the lower cutter 44 and the peripheral edge portion of the upper cutter 43 in engagement therewith and both cutters 43, 44 are shapened by each other during rotation, by the friction therebetween providing for a smooth cutting operation.

In the embodiment shown in FIG. 3, the distance between the upright portion 78 of the table 11 against which one edge of the envelope E is urged by the coaction of the feed rollers 57, 61, and the place of engagement between the upper and lower cutters is constant and hence the width of the cut chip of the envelope is unchanged.

However, by arranging the mechanism as shown in FIGS. 11 and 12, the distance between the place of engagement between boh cutters and the upright portion of the table can be varied and, therefore, the width of the cut chip can also be varied.

The embodiment of the power-operated envelope opener shown in FIGS. 11 and 12 is of the substantially same construction as that shown in FIGS. 3 and 4, except for the table. In this embodiment, an oval hole 105 is formed in the horizontal portion 24 of the base plate 23 for inspecting the intermeshing arrangement of the gears therethrough at the time of installation of the motor 25. Such an opening may be formed in the power operated envelope opener shown in FIGS. 3 and 4.

A table 106 for placing an envelope to be cut thereon does not have an upright portion and a pentroof as shown in FIGS. 3 and 4 per se, which form a guide for the envelope, and instead flexed members 107a, 1071; are fixed to the upright portion 31 of the base plate 23 by means of bolts 108, with one sections thereof extending downwardly. Further, the portion of the table 106 close to the upright portion 31 of the base plate 23 is slightly stepped downwardly along the longitudinal direction of said table as indicated by numeral 109 in FIG. 13, to form a small table mounting portion 110 which is lower than the other portion of the table by about 1 mm which corresponds to the thickness of a small table, as shown in FIG. 13. Wavy slots 111 are formed in the small table mounting portion 110 at a predetermined interval between each other, as shown in FIG. 20, for receiving pins provided on the small table.

The small table, generally indicated by reference numeral 112 and placed on the small table mounting portion 110, is formed in an L-shape consisting of a flat portion 113 of a width smaller than the width of said portion 110 and an upright portion 114 extending upright from the edge of said flat portion 113, but the flat portion 113 is cut away from a portion close to the switch actuating lever 66 to the right end of the table 106. The upper edge of the upright portion 114 is integrally formed with a pentrool 115 which is slightly smaller in width than that in the embodiment of FIG.

3 and by which curling of the envelope is prevented. As-

is clearly seen in FIGS. 17 and 18, the small table 112 has a downwardly flexed lug 116 and a rightwardly flexed lug 117 formed at the left end and the right end thereof respectively, so that said small table may be easily displaced horizontally in sliding engagement with the table 106. The entire length of the small table 112 is slightly larger than the length of the table 106.

Two pins 118a, l18b are fixed at their upper ends to the underside of the flat portion 113 of the small table 112 at a predetermined interval therebetween to extend downwardly therefrom. These pins 118a, 118b extend downwardly through the wavy slots 111 formed in the small table mounting portion 110 of the table 106 respectively, and a coil spring 119 as shownin FIG.

21 and one loop end of a tension spring 120 and a plain washer 121, also shown in FIG. 21, are mounted around the projecting end of each pin 1180 or or 118b between the undersurface of the small table mounting portion of the table 106 and an E-shaped washer 122 fixedly mounted on the lower end of said pin. Thus, it will be understood that the flat portion 113 of the small table 112 is constantly urged against the portion 110 of the table 106 under the biasing force of the springs 119 and held against upward movement. As shown in FIGS. 11 and 12, windows 123a, 12312 are formed in the upright portion 31 of the base plate 23 at two locations by cut-bending said upright portion and the resultant cut-bent lugs 124a, 1241) are inwardly flexed through an angle of 90 over the horizontal portion 24. The other ends of the aforesaid tension springs are anchored to the outer edges of the correspond ing cut-bent lugs 124a, 1241) through the windows respectively.

Each of the wavy slots 111 has three substantially arcuate engaging portions a, b and c which are communicated with each other through a curved portion of the slot. When the pins 118a, 118b of the small table 112 are positioned in ones of these engaging portions of the respective wavy slots 111, the small table 112 is held stationary in its position under the biasing force of the tension spring 120. When the small table 112 is held stationary with the pins 118a, 1181; in engagement with the engaging portions a of the wavy slots 111, the distance A between the upright portion 114 of said small table and the place of contact between the upper and lower cutters 43, 445, is smallest as shown in FIG. 13 and accordingly the width of the cut chip of the envelope becomes small. It is essential that, even when the upright portion of the small table is :in a position closest to the place of contact between the cutters, a space as indicated by B be maintained between said upright portion and the lower cutter 44, to ensure that they will not contact each other. Now, when the two pins are moved off the engaging portions a of the sllots 111 against the biasing forces of the tension springs, by either pushing the left end lug 116 or pulling the right end lug 117 of the small table and placed in the next engaging portions [7 respectively, the small table 112 is displaced slightly rightwardly and the upright portion 114 thereof gets close to the upright portion 31 of the base plate and the distance from the place of contact between the cutters to the upright portion 114 of the small table is increased by an amount equal to the substantial distance between the engaging portions a and b in the transverse direction of the small table, with the result that the width of the cut chip of the envelope can be increased.

Where it is desired to obtain a cut chip of a width equal to the thickness of the cutting portion of the lower cutter 44, this cannot be attained with the small table having the rectilinear upright portion 114 as shown in FIGS. 17 and 18 because said upright portion 114 contacts the backside of the lower cutter 44. In such a case, use is made of a small table as shown in FIGS. 14, 15 and 16. The small table shown in these Figures is so constructed that a portion of the upright portion 114 thereof, i.e. the portion opposite to the lower cutter 44, is bulged outwardly (toward the upright portion of the base plate) by a distance greater than the thickness of the lower cutter 44, to form a shallow recess 125. The depth of this: recess 125 should be at least equal to the thickness of the cutting portion of the lower cutter 44 and preferably is greater than the latter in consideration of a production error and a deflection of the cutter caused by improper use of the opener. With the shallow recess 125 formed at the portion of the upright member of the small table opposite to the cutter as described above, it is possible to cut one edge of the envelope in a width equal to the thickness of the cutting portion of the lower cutter 44, even when the upright portion of the small table is located closest to the cutter and the portion of the upright portion other than said recess 125 is located in the same plane as the backside of the lower cutter 44. It will be understood that in the envelope opening operation the interval between the upright portion 114 of the small table 112 and the place of contact between the cutters 43, 44, i.e. the width of the cut chip, can be known by providing cutting width indicator markings I, II and III on the sloped portion of the table 106 and a cooperating marking X on the flat portion 113 of the small table 112, as at 126 in FIG. 11.

Although in the two embodiments of the invention described and illustrated herein, the lower one of the two cooperating cutters is very slightly inclined relative to the direction of travel of envelope so as to produce an acute angular contact between the peripheral edge portions of said cutters, it should be understood that such acute angular contact may also be obtained by slightly inclining the bearing for the rotary shaft of the upper cutter relative to a line normal to the upright portion 31 of the base plate, to cut satisfactorily an envelope being fed by the feed rollers. However, it is disadvantageous and should be avoided to incline both the upper and lower cutter relative to the travelling direction of envelope, because a smooth meshing of the power transmitting gears and hence a smooth rotation of the cutters cannot be obtained.

It is also to be understood that, while in the embodiments shown the lower cutter, driven at a higher rate of speed, is made relatively large in diameter and the upper cutter, driven at a lower rate of speed, is made relatively small in diameter, so as to differentiate the peripheral speeds of both cutters and thereby to produce a mutual sharpening effect of said cutters, the upper and lower cutters may be of the same diameter. It is, however, undesirable to use a cutter of a relatively large diameter for the lower cutter driven at a higher rate of speed and a cutter of a relatively small diameter for the upper cutter driven at a lower rate of speed, because, since the cutters rub each other so intensely, the tendency of the lower cutter being worn off by the upper cutter increases rather than the cutters are sharpened by each other.

In the embodiments described and illustrated herein, each cutter used is in the shape of a disc having a tapered edge and, therefore, the envelope is cut ina straight line. In order to cut the envelope to have a serrated cut edge, a cutter in the shape of roulette, having triangular cutting teeth formed at a predetermined pitch on the tapered edge thereof, may be used for the upper cutter. The cutter of this type enables a serrated cut edge of envelope to be obtained even when used with the disc-shaped lower cutter. Further, although a satisfactory cutting operation can be obtained by using this type of cutter for only the upper cutter, it may be used for both the upper and lower cutters.

It should also be understood that the gears and the tables may be made of materials other than those specifled herein, depending upon the purpose of use and the cost of the opener.

Many other changes and modifications can be made to the details of the present invention described herein, without deviating from the spirit of the invention.

What is claimed is:

1. An automatic feeding, power-operated envelope opener comprising cutter means including a pair of rotary shafts journaled one above the other in an upright portion of a base plate with a slight inclination relative to each other in a horizontal plane including one of said shafts and driven from a motor, said shafts being substantially aligned with each other in a vertical direction, and disc-shaped cutters each having a taper at the peripheral edge portion of one side and a shallow depression on the other side respectively mounted on said rotary shafts in such a manner that the peripheral edge portions thereof make a point contact with each other at an acute angle to penetrate into the envelope in the manner of wedge, an electric motor constituting a drive source for said shafts, a table for mounting the envelope thereon, an on-off switch for controlling the current supply to the opener, a switch actuating lever for actuating said switch to supply current to said electric motor upon being operated by the envelope travelling on said table, a feed roller for feeding the envelope to said cutter means and a transmission gearing for transmitting the drive of said electric motor to said cutter means and said envelope feeding roller.

2. An automatic feeding, power-operated envelope opener as defined in claim 1, wherein said table is secured at one edge portion to said base plate, said one edge portion being flexed into a U-shaped cross-section to form an upright portion and a pentroof and the portion of said upright portion from the mid portion between said feed roller and said cutter means to one end of the table is bulged to be spaced from the plane of contact between said cutters, whereby the interval between said upright portion and said cutter means is increased at said bulged portion.

3. An automatic feeding, power-operated envelope opener as defined in claim 1, wherein the disc-shaped cutter mounted on the upper rotary shaft is larger in diameter than the disc-shaped cutter mounted on the lower rotary shaft and driven at a lower peripheral speed than that of said latter disc-shaped cutter.

4. An automatic feeding, power operated envelope opener as defined in claim 1, wherein the disc-shaped cutter mounted on the upper rotary shaft and the discshaped cutter mounted on the lower rotary shaft are of the same diameter and the latter is driven at a higher peripheral speed than that of the former.

5. An automatic feeding, power-operated envelope opener comprising an L-shaped base plate having a horizontal portion and an upright portion; an electric motor constituting a drive source and fixedly mounted on the horizontal portion of said L-shaped base plate; cutter means consisting of two cutters fixed to the upright portion of said base plate through rotary shafts respectively one on top of another and driven in contact 1 with each other, one of said cutters being parallel to and the other one of the same being inclined at a very small angle to the direction of travel of an envelope to be cut; a feed roller for feeding the envelope to said cutter means; an on-off switch for controlling the current supply to said electric motor; a switch actuating lever for actuating said switch upon being operated by the travelling envelope; a gearing for transmitting the drive of said electric motor to said cutter means and said feed roller; said feed roller, said switch, said switch actuating lever and said gearing being mounted on the upright portion of said base plate; a table having an edge thereof flexed into a U-shaped cross-section to form an upright portion and a pentroof and fixed to the upright portion of said base plate at said flexed edge to extend forward therefrom; a box-shaped case having two relatively high legs at the forward portion and two relatively low legs at the rear portion of the bottom surface thereof and having said L-shaped base plate fixedly mounted therein with said respective elements mounted thereon in such a way that the table side of the opener will be higher than the motor side when said opener is set in an operative position; and a cover closing the top opening of said case.

6. An automatic feeding, power-operated envelope opener as defined in claim 5, wherein air suction openings are formed in the rear end wall and air discharge apertures are formed in the bottom wall of said case.

7. An automatic feeding, power-operated envelope opener as defined in claim 5, wherein a cooling fan is connected to one end of the drive shaft of said electric motor for cooling said electric motor by blowing air directly thereagainst and serving simultaneously as a flywheel for smoothening the rotation of said motor.

8. An automatic feeding, power-operated envelope opener as defined in claim 5, wherein four inward depressions are formed in the bottom wall of said case to form leg mounting seats each having an oval hole centrally formed in the inwardly raised portion thereof, and said two relatively high legs are mounted in the oval holes of the two of said leg mounting seats located at forward portion of the bottom wall of said case and said two relatively low legs in the oval holes of the other two of said leg mounting seats located at the rear por tion of the same, each of said relatively high legs comprising a tapered main body having an inclined bottom surface and having a bolt receiving bore axially formed therein from said inclined bottom surface to the mid portion thereof, an engaging portion having a crosssectional shape same as the shape of said oval hole and a circular flange formed on top of said engaging portion, all of which are integrally molded of a synthetic rubber, said relatively low legs having the same shape and molded of the same material as said relatively high legs but being only shorter than the latter, and further said L-shaped base plate is mounted in said case with the horizontal portion thereof resting on the flanges of said four legs and tightened to said case together with said legs by means of bolts extending through said respective legs.

9. An automatic feeding, power-operated envelope opener as defined in claim 5, wherein said cover has the forward portion thereof cut away to form an opening and is formed with projections on the inside surfaces of the opposite side walls thereof each with a nut embedded therein for engagement with a tightening bolt, rectangular lips extending downwardly from the lower edges of the opposite side walls thereof at the locations where said side walls are cut away to form the opening and a continuous step in the lower edges of the side walls and the end wall thereof for interlocking engagement with the upper edge of said case, while said case is formed with rectangular recesses in the upper edges of the opposite side walls thereof for interlocking en- 14 gagement with said rectangular lips, and said cover and said case are integrally combined together by the tightening bolts extending through said case and screw threaded into said nuts respectively.

10. An automatic feeding, power-operated envelope opener as defined in claim 5, wherein two cylindrical projections are formed on the upright portion of said L-shaped base plate one above another, one of which is very slightly inclined in a substantially horizontal plane relative to a line normal to said upright portion, and a sleeve-shaped bearing metal is inserted into each of said cylindrical projection in force-fit engagement therewith, into which the rotary shaft having the cutter fixedly mounted on one end thereof is journaled.

11. An automatic feeding, power-operated envelope opener comprising an L-shaped base plate having a horizontal portion and an upright portion; an electric motor constituting a drive source and fixedly mounted on the horizontal portion of said L-shaped base plate; cutter means consisting of two cutters fixed to the upright portion of said base plate through rotary shafts respectively one on top of another and driven in contact with each other, one of said cutters being parallel to and the other one of the same being inclined at a vey small angle to the direction of travel of an envelope to be cut; a feed roller for feeding the envelope to said cutter means; an on-off switch for controlling the current supply to said electric motor; a switch actuating lever for actuating said switch upon being operated by the travelling envelope; a gearing for transmitting the drive of said electric motor to said cutter means and said feed roller; said feed roller, said. switch, said switch actuating lever and said gearing being mounted on the upright portion of said base plate; a table for mounting the envelope thereon extending forward from said base plate and having the edge portion adjacent said base plate stepped slightly downwardly along the longitudinal direction thereof; and a substantially L-shaped small table mounted on said stepped portion of said table for sliding movement thereon in the longitudinal direction thereof while being simultaneously shifted in the transverse direction and consisting of a flat portion and an upright portion with the upper edge thereof flexed to form a pentroof.

12. An automatic feeding, power-operated envelope opener as defined in claim 11, wherein said stepped portion of said table is formed therein with at least two wavy slots, while the flat portion of said small table is provided with at least two pins for engagement with said respective wavy slots, and a coil spring to constantly urge the flat portion of said small table against the stepped portion of said table and one loop end of a tension spring to hold said pins in a selected ones of engaging portions of said respective wavy slots under the biasing force thereof are mounted around each of said pins, the other loop end of said coil spring being anchored to a cut-bent lug formed on the upright portion of said L-shaped base plate.

13. An automatic feeding, power-operated envelope opener as defined in claim 11, wherein the upright portion of said small table is bulged outwardly at a portion opposite to the cutter means to form a recessed portion of a width wider than the width of said cutter means.

14. An automatic feeding, power-operated envelope opener as defined in claim 11, wherein a downwardly projecting lug and a rightwardly projecting lug are formed at the longitudinal opposite ends of said small table respectively to facilitate movement of said small table and means for indicating the width of the cut chip of an envelope is provided which consists of a marking provided on the flat portion of said small table and cooperating markings provided on the stepped portion of said table. 

1. An automatic feeding, power-operated envelope opener comprising cutter means including a pair of rotary shafts journaled one above the other in an upright portion of a base plate with a slight inclination relative to each other in a horizontal plane including one of said shafts and driven from a motor, said shafts being substantially aligned with each other in a vertical direction, and disc-shaped cutters each having a taper at the peripheral edge portion of one side and a shallow depression on the other side respectively mounted on said rotary shafts in such a manner that the peripheral edge portions thereof make a point contact with each other at an acute angle to penetrate into the envelope in the manner of wedge, an electric motor constituting a drive source for said shafts, a table for mounting the envelope thereon, an on-off switch for controlling the current supply to the opener, a switch actuating lever for actuating said switch to supply current to said electric motor upon being operated by the envelope travelling on said table, a feed roller for feeding the envelope to said cutter means and a transmission gearing for transmitting the drive of said electric motor to said cutter means and said envelope feeding roller.
 2. An automatic feeding, power-operated envelope opener as defined in claim 1, wherein said table is secured at one edge portion to said base plate, said one edge portion being flexed into a U-shaped cross-section to form an upright portion and a pentroof and the portion of said upright portion from the mid portion between said feed roller and said cutter means to one end of the table is bulged to be spaced from the plane of contact between said cutters, whereby the interval between said upright portion and said cutter means is increased at said bulged portion.
 3. An automatic feeding, power-operated envelope opener as defined in claim 1, wherein the disc-shaped cutter mounted on the upper rotary shaft is larger in diameter than the disc-shaped cutter mounted on the lower rotary shaft and driven at a lower peripheral speed than that of said latter disc-shaped cutter.
 4. An automatic feeding, power operated envelope opener as defined in claim 1, wherein the disc-shaped cutter mounted on the upper rotary shaft and the disc-shaped cutter mounted on the lower rotary shaft are of the same diameter and the latter is driven at a higher peripheral speed than that of the former.
 5. An automatic feeding, power-operated envelope opener comprising an L-shaped base plate having a horizontal portion and an upright portion; an electric motor constituting a drive source and fixedly mounted on the horizontal portion of said L-shaped base plate; cutter means consisting of two cutters fixed to the upright portion of said base plate through rotary shafts respectively one on top of another and driven in contact with each other, one of said cutters being parallel to and the other one of the same being inclined at a very small angle to the direction of travel of an envelope to be cut; a feed roller for feeding the envelope to said cutter means; an on-off switch for controlling the current supply to said electric motor; a switch actuating lever for actuating said switch upon being operated by the travelling envelope; a gearing for transmitting the drive of said electric motor to said cutter means and said feed roller; said feed roller, said switch, said switch actuating lever and said gearing being mounted on the upright portion of said baSe plate; a table having an edge thereof flexed into a U-shaped cross-section to form an upright portion and a pentroof and fixed to the upright portion of said base plate at said flexed edge to extend forward therefrom; a box-shaped case having two relatively high legs at the forward portion and two relatively low legs at the rear portion of the bottom surface thereof and having said L-shaped base plate fixedly mounted therein with said respective elements mounted thereon in such a way that the table side of the opener will be higher than the motor side when said opener is set in an operative position; and a cover closing the top opening of said case.
 6. An automatic feeding, power-operated envelope opener as defined in claim 5, wherein air suction openings are formed in the rear end wall and air discharge apertures are formed in the bottom wall of said case.
 7. An automatic feeding, power-operated envelope opener as defined in claim 5, wherein a cooling fan is connected to one end of the drive shaft of said electric motor for cooling said electric motor by blowing air directly thereagainst and serving simultaneously as a flywheel for smoothening the rotation of said motor.
 8. An automatic feeding, power-operated envelope opener as defined in claim 5, wherein four inward depressions are formed in the bottom wall of said case to form leg mounting seats each having an oval hole centrally formed in the inwardly raised portion thereof, and said two relatively high legs are mounted in the oval holes of the two of said leg mounting seats located at forward portion of the bottom wall of said case and said two relatively low legs in the oval holes of the other two of said leg mounting seats located at the rear portion of the same, each of said relatively high legs comprising a tapered main body having an inclined bottom surface and having a bolt receiving bore axially formed therein from said inclined bottom surface to the mid portion thereof, an engaging portion having a cross-sectional shape same as the shape of said oval hole and a circular flange formed on top of said engaging portion, all of which are integrally molded of a synthetic rubber, said relatively low legs having the same shape and molded of the same material as said relatively high legs but being only shorter than the latter, and further said L-shaped base plate is mounted in said case with the horizontal portion thereof resting on the flanges of said four legs and tightened to said case together with said legs by means of bolts extending through said respective legs.
 9. An automatic feeding, power-operated envelope opener as defined in claim 5, wherein said cover has the forward portion thereof cut away to form an opening and is formed with projections on the inside surfaces of the opposite side walls thereof each with a nut embedded therein for engagement with a tightening bolt, rectangular lips extending downwardly from the lower edges of the opposite side walls thereof at the locations where said side walls are cut away to form the opening and a continuous step in the lower edges of the side walls and the end wall thereof for interlocking engagement with the upper edge of said case, while said case is formed with rectangular recesses in the upper edges of the opposite side walls thereof for interlocking engagement with said rectangular lips, and said cover and said case are integrally combined together by the tightening bolts extending through said case and screw threaded into said nuts respectively.
 10. An automatic feeding, power-operated envelope opener as defined in claim 5, wherein two cylindrical projections are formed on the upright portion of said L-shaped base plate one above another, one of which is very slightly inclined in a substantially horizontal plane relative to a line normal to said upright portion, and a sleeve-shaped bearing metal is inserted into each of said cylindrical projection in force-fit engagement therewith, into which the rotary shaft having the cutter fixedly mounted on one end thereof is journaled.
 11. An automatic feeding, power-operated envelope opener comprising an L-shaped base plate having a horizontal portion and an upright portion; an electric motor constituting a drive source and fixedly mounted on the horizontal portion of said L-shaped base plate; cutter means consisting of two cutters fixed to the upright portion of said base plate through rotary shafts respectively one on top of another and driven in contact with each other, one of said cutters being parallel to and the other one of the same being inclined at a vey small angle to the direction of travel of an envelope to be cut; a feed roller for feeding the envelope to said cutter means; an on-off switch for controlling the current supply to said electric motor; a switch actuating lever for actuating said switch upon being operated by the travelling envelope; a gearing for transmitting the drive of said electric motor to said cutter means and said feed roller; said feed roller, said switch, said switch actuating lever and said gearing being mounted on the upright portion of said base plate; a table for mounting the envelope thereon extending forward from said base plate and having the edge portion adjacent said base plate stepped slightly downwardly along the longitudinal direction thereof; and a substantially L-shaped small table mounted on said stepped portion of said table for sliding movement thereon in the longitudinal direction thereof while being simultaneously shifted in the transverse direction and consisting of a flat portion and an upright portion with the upper edge thereof flexed to form a pentroof.
 12. An automatic feeding, power-operated envelope opener as defined in claim 11, wherein said stepped portion of said table is formed therein with at least two wavy slots, while the flat portion of said small table is provided with at least two pins for engagement with said respective wavy slots, and a coil spring to constantly urge the flat portion of said small table against the stepped portion of said table and one loop end of a tension spring to hold said pins in a selected ones of engaging portions of said respective wavy slots under the biasing force thereof are mounted around each of said pins, the other loop end of said coil spring being anchored to a cut-bent lug formed on the upright portion of said L-shaped base plate.
 13. An automatic feeding, power-operated envelope opener as defined in claim 11, wherein the upright portion of said small table is bulged outwardly at a portion opposite to the cutter means to form a recessed portion of a width wider than the width of said cutter means.
 14. An automatic feeding, power-operated envelope opener as defined in claim 11, wherein a downwardly projecting lug and a rightwardly projecting lug are formed at the longitudinal opposite ends of said small table respectively to facilitate movement of said small table and means for indicating the width of the cut chip of an envelope is provided which consists of a marking provided on the flat portion of said small table and cooperating markings provided on the stepped portion of said table. 